The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61.

An update of the nss package has been released.

The remote Ubuntu 20.04 LTS / 22.04 LTS / 23.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6727-1 advisory.

    It was discovered that NSS incorrectly handled padding when checking PKCS#1 certificates. A remote     attacker could possibly use this issue to perform Bleichenbacher-like attacks and recover private data.
    This issue only affected Ubuntu 20.04 LTS. (CVE-2023-4421)

    It was discovered that NSS had a timing side-channel when performing RSA decryption. A remote attacker     could possibly use this issue to recover private data. (CVE-2023-5388)

    It was discovered that NSS had a timing side-channel when using certain NIST curves. A remote attacker     could possibly use this issue to recover private data. (CVE-2023-6135)

    The NSS package contained outdated CA certificates. This update refreshes the NSS package to version 3.98     which includes the latest CA certificate bundle and other security improvements.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3634 advisory.

  - A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3. This flaw allows a     remote attacker to send multiple CCS messages, causing a denial of service for servers compiled with the     NSS library. The highest threat from this vulnerability is to system availability. This flaw affects NSS     versions before 3.58. (CVE-2020-25648)

  - new tlsfuzzer code can still detect timing issues in RSA operations (CVE-2023-4421) (CVE-2023-4421)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of nss-softokn installed on the remote host is prior to 3.53.1-6.48. It is, therefore, affected by a vulnerability as referenced in the ALAS-2023-1858 advisory.

  - new tlsfuzzer code can still detect timing issues in RSA operations (CVE-2023-4421) (CVE-2023-4421)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
204001	Photon OS 3.0: Nss PHSA-2024-3.0-0716	Nessus	PhotonOS Local Security Checks	medium
193171	Ubuntu 20.04 LTS / 22.04 LTS / 23.10 : NSS vulnerabilities (USN-6727-1)	Nessus	Ubuntu Local Security Checks	medium
183996	Debian DLA-3634-1 : nss - LTS security update	Nessus	Debian Local Security Checks	medium
183847	Amazon Linux AMI : nss-softokn (ALAS-2023-1858)	Nessus	Amazon Linux Local Security Checks	medium

Detections

Analytics

CVE-2023-4421

medium

Tenable Plugins

medium

medium

medium

medium